Computer Hardware Familiarization Part-5.

For part 5 of this post we now go into the external components of the computer hardware. We three primary items for these post, the monitor, pointing device and keyboard.

The Computer monitor

A monitor or display (also called screen or visual display unit) is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) thin panel, while older monitors use a cathode ray tube about as deep as the screen size.

Originally, computer monitors were used for data processing while television receivers were used for entertainment. From the 1980s onwards, computers (and their monitors) have been used for both data processing and entertainment, while televisions have implemented some computer functionality. The common aspect ratio of televisions, and then computer monitors, has also changed from 4:3 to 16:9.

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Image via Wikipedia

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The first computer monitors used cathode ray tubes (CRT). Until the early 1980s, they were known as video display terminals and were physically attached to the computer and keyboard. The monitors were monochrome, flickered and the image quality was poor In 1981, IBM introduced the Color Graphics Adapter, which could display four colors with a resolution of 320 by 200 pixels. In 1984 IBM introduced the Enhanced Graphics Adapter which was capable of producing 16 colors and had a resolution of 640 by 350.

CRT remained the standard for computer monitors through the 1990s. CRT technology remained dominant in the PC monitor market into the new millennium partly because it was cheaper to produce and offered viewing angles close to 180 degrees.

^{Liquid Crystal Display}

There are multiple technologies that have been used to implement Liquid Crystal Displays (LCDs). Throughout the 1990s the primary use of LCD technology as computer monitors was in laptops where the lower power consumption, lighter weight, and smaller physical size of LCDs justified the higher price versus a CRT. Commonly, the same laptop would be offered with an assortment of display options at increasing price points (active or passive) monochrome, passive color, active matrix color (TFT). As volume and manufacturing capability have improved the monochrome and passive color technologies were dropped from most product lines.

The pointing device

A pointing device is an input interface (specifically a human interface device) that allows a user to input spatial (i.e., continuous and multi-dimensional) data to a computer. CAD systems and graphical user interfaces (GUI) allow the user to control and provide data to the computer using physical gestures — point, click, and drag — for example, by moving a hand-held mouse across the surface of the physical desktop and activating switches on the mouse. Movements of the pointing device are echoed on the screen by movements of the pointer (or cursor) and other visual changes.

While the most common pointing device by far is the mouse, many more devices have been developed. A "rodent" is a technical term referring to a device which generates mouse-like input. However, the term "mouse" is commonly used as a metaphor for devices that move the cursor.

Image via Wikipedia

Image via Wikipedia

Image via Wikipedia

Image via Wikipedia

Image via Wikipedia

 The mouse is the most common representation of the computer pointing device. Most of us point to the mouse as the only pointing device, but based on the picture above pointing  cane vary in size and form. Another type of pointing device that is similar to the mouse is the Trackball.

A trackball is a pointing device consisting of a ball housed in a socket containing sensors to detect rotation of the ball about two axes, similar to an upside-down mouse: as the user rolls the ball with a thumb, fingers, or palm the pointer on the screen will also move. Tracker balls are commonly used on CAD workstations for ease of use, where there may be no desk space on which to use a mouse. Some are able to clip onto the side of the keyboard and have buttons with the same functionality as mouse buttons. There are also wireless trackballs which offer a wider range of ergonomic positions to the user.

The computer keyboard

In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. Following the decline of punch cards and paper tape, interaction via teleprinter-style keyboards became the main input device for computers.

Despite the development of alternative input devices, such as the mouse, touchscreen, pen devices, character recognition and voice recognition, the keyboard remains the most commonly used and most versatile device used for direct (human) input into computers.

A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or computer commands.

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Image via Wikipedia

Image by Getty Images via @daylife

Image via Wikipedia

Image by Getty Images via @daylife

Standard "full-travel" alphanumeric keyboards have keys that are on three-quarter inch centers (0.750 inches, 19.05 mm), and have a key travel of at least 0.150 inches (3.81 mm). Desktop computer keyboards, such as the 101-key US traditional keyboards or the 104-key Windows keyboards, include alphabetic characters, punctuation symbols, numbers and a variety of function keys. The internationally common 102/105 key keyboards have a smaller 'left shift' key and an additional key with some more symbols between that and the letter to its right (usually Z or Y). Also the 'enter' key is usually shaped differently. Computer keyboards are similar to electric-typewriter keyboards but contain additional keys. Standard USB keyboards can also be connected to some non-desktop devices.

We are now almost complete in our familiarization series post about the basic computer hardware. My next will tackle some hardware accessories that you might be interested to really dress up your computer.

Computer 101: The Display (CRT to LCD to LED and to the Future.)

Computer based technology from the processor, main board, memory, storage, interface and even power source and consumption is getting smaller in size but in turn they become faster still has become bigger in terms of capacity and also more importantly the power source has also become smaller but pack more power in them compared to their ancestors.

An example of this technology is all around us, the first to be created in smaller size is the processor. The processor is the brain of most electronic devices of today. Even circuit that is being used in almost embedded system has a processor in them for better management and control. Then the main board follows suit, or is that simultaneous with the processor. Small processor needs smaller main board, memory and power source. But wait before we moved any further, a key missing component of the computer is missing. This key component is the display.

I don’t know if it is intentional but the primary computer display for many years was the old reliable CRT Screen or the Cathode Ray-Tube. We have seen fast technological advances in almost all area of the computer. From the processor, memory, main board and even the power supply yet while all of this is going on, the computer display seems stock on the CRT as its primary display device. I still can clearly remember playing may old hand held game device called game and watch and it uses a black and white LCD display back then.

During those times the CRT is still in green test with black background and a newer black and white display is the new pad then, the colored display is still being developed. Then after a few years the colored came and a whole new world open, but still the technology used for most computer is still the CRT type. Whether it is just a VGA, SVGA, XGA and many others still the computer primary screen display is the CRT. Back then almost small electronic device has a small black and white LCD display, then why in the world the computer cannot have an LCD as a display monitor. It consumes less power considerably then the CRT technology and very easy to carry because it weights less and a small space is required to put it.

This image is from Photorack.net

Even with the advent of the new millennium, the CRT is still the supreme display device for the computer. Not even with the coming of the first generation of wireless phone can change the main display device for the computer. Notice that the early cell phone was already small compare to its cousin. Also the cell phone technology was very much in high gear ever evolving continuously. Notice how the slow the evolution of the display has drag on for decades before the CRT was slowly replaced by the first generation LCD display.  By that time every electronic device that needs a screen has a small colored screen attached to them. Only when the development of the smart phone, came a faster technology development for the display. Suddenly the CRT was outdated and was being replaced by the LCD. Then from the LCD another technology would become the foundation for a new generation of display for all electronic devices this computer was not left out. Actually this technology is not new it’s been around for many decades now.

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This technology is the LED or the Light Emitting Diode, the LED was refine, is became smaller and smaller until it become small enough that hundred of LED can be put in your palm.  With the characteristic of having even lower power consumption and durability than its predecessor. The LED has evolve a lot faster is now the choice of display for most electronic device like the present day generation of smart phone. We now have OLED (Organic-LED) based display meaning the LED has leap forward by becoming more green and sustainable. Other display technology has also evolve the Retina Display use in some high end phone this is just one of the display technology available today.

Now finally the computer has come a long way from the old big CRT to the thin LCD, LED, OLED and many others. The display has finally come with age as with all the other computer based technology that have been continuously evolving. The display technology has now become at par with the other development in computer based technologies.  

Note:

For more information regarding the OLED Technology, Please click the link below:

Organic LED in Wikipedia

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